mirror of
https://github.com/libretro/scummvm.git
synced 2024-12-16 06:39:17 +00:00
192 lines
4.7 KiB
C++
192 lines
4.7 KiB
C++
/* ScummVM - Graphic Adventure Engine
|
|
*
|
|
* ScummVM is the legal property of its developers, whose names
|
|
* are too numerous to list here. Please refer to the COPYRIGHT
|
|
* file distributed with this source distribution.
|
|
*
|
|
* This program is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
*/
|
|
|
|
#include "math/line2d.h"
|
|
#include "math/rect2d.h"
|
|
|
|
namespace Math {
|
|
|
|
/* Linear equation used to describe the line:
|
|
*
|
|
* Ax + By = C
|
|
*
|
|
*/
|
|
|
|
Line2d::Line2d(const Vector2d &direction, const Vector2d &point) {
|
|
_a = direction.getX();
|
|
_b = direction.getY();
|
|
_c = point.getY() * (point.getX() + direction.getX()) - point.getX() * (point.getY() + direction.getY());
|
|
}
|
|
|
|
Line2d Line2d::getPerpendicular(const Vector2d &point) const {
|
|
return Line2d(Vector2d(_a, _b), point);
|
|
}
|
|
|
|
Vector2d Line2d::getDirection() const {
|
|
return Vector2d(-_b, _a);
|
|
}
|
|
|
|
float Line2d::getDistanceTo(const Vector2d &point, Vector2d *intersection) const {
|
|
float dist = fabsf(_a * point.getX() + _b * point.getY() - _c) / sqrt(_a * _a + _b * _b);
|
|
|
|
if (intersection) {
|
|
intersectsLine(getPerpendicular(point), intersection);
|
|
}
|
|
return dist;
|
|
}
|
|
|
|
bool Line2d::intersectsLine(const Line2d &line, Vector2d *pos) const {
|
|
float a1 = _a;
|
|
float b1 = _b;
|
|
float c1 = _c;
|
|
|
|
float a2 = line._a;
|
|
float b2 = line._b;
|
|
float c2 = line._c;
|
|
|
|
float x, y;
|
|
|
|
const float det = a1 * b2 - b1 * a2;
|
|
|
|
if (fabsf(det) < epsilon) {
|
|
return false;
|
|
}
|
|
|
|
x = (c1 * b2 - c2 * b1) / det;
|
|
y = (a1 * c2 - a2 * c1) / det;
|
|
|
|
if (pos)
|
|
*pos = Vector2d(x, y);
|
|
|
|
return true;
|
|
}
|
|
|
|
bool Line2d::containsPoint(const Vector2d &point) const {
|
|
float n = _a * point.getX() + _b * point.getY() - _c;
|
|
return (fabsf(n) < epsilon);
|
|
}
|
|
|
|
Common::StreamDebug &operator<<(Common::StreamDebug &dbg, const Math::Line2d &line) {
|
|
if (fabsf(line._a) < epsilon) {
|
|
dbg.nospace() << "Line2d: <y = " << (-line._a / line._b) << " * x + " << line._c / line._b << ">";
|
|
} else {
|
|
dbg.nospace() << "Line2d: <x = " << (-line._b / line._a) << " * y + " << line._c / line._a << ">";
|
|
}
|
|
|
|
return dbg.space();
|
|
}
|
|
|
|
|
|
Segment2d::Segment2d() {
|
|
}
|
|
|
|
Segment2d::Segment2d(const Vector2d &b, const Vector2d &e) :
|
|
_begin(b), _end(e) {
|
|
}
|
|
|
|
Segment2d::Segment2d(const Segment2d &other) {
|
|
*this = other;
|
|
}
|
|
|
|
Vector2d Segment2d::begin() const {
|
|
return _begin;
|
|
}
|
|
|
|
Vector2d Segment2d::end() const {
|
|
return _end;
|
|
}
|
|
|
|
Vector2d Segment2d::middle() const {
|
|
return (_begin + _end) / 2.f;
|
|
}
|
|
|
|
Line2d Segment2d::getLine() const {
|
|
float y = _end.getY() - _begin.getY();
|
|
float x = _end.getX() - _begin.getX();
|
|
Vector2d v(x, y);
|
|
|
|
return Line2d(v, _begin);
|
|
}
|
|
|
|
Line2d Segment2d::getPerpendicular(const Vector2d &point) const {
|
|
return getLine().getPerpendicular(point);
|
|
}
|
|
|
|
bool Segment2d::intersectsSegment(const Segment2d &other, Vector2d *pos) {
|
|
float denom = ((other._end.getY() - other._begin.getY()) * (_end.getX() - _begin.getX())) -
|
|
((other._end.getX() - other._begin.getX()) * (_end.getY() - _begin.getY()));
|
|
|
|
|
|
float d = ((_end.getY() - _begin.getY()) * (other._end.getX() - other._begin.getX())) -
|
|
((_end.getX() - _begin.getX()) * (other._end.getY() - other._begin.getY()));
|
|
|
|
float nume_a = ((other._end.getX() - other._begin.getX()) * (_begin.getY() - other._begin.getY())) -
|
|
((other._end.getY() - other._begin.getY()) * (_begin.getX() - other._begin.getX()));
|
|
|
|
float nume_b = ((_end.getX() - _begin.getX()) * (other._begin.getY() - _begin.getY())) -
|
|
((_end.getY() - _begin.getY()) * (other._begin.getX() - _begin.getX()));
|
|
|
|
if (denom == 0.0f || d == 0.0f ) {
|
|
return false;
|
|
}
|
|
|
|
float ua = nume_a / denom;
|
|
float ub = nume_b / d;
|
|
|
|
if (ua < 0.0f || ua > 1.0f || ub < 0.0f || ub > 1.0f) {
|
|
return false;
|
|
}
|
|
|
|
// Get the intersection point.
|
|
if (pos)
|
|
*pos = _begin + (_end - _begin) * ua;
|
|
|
|
return true;
|
|
}
|
|
|
|
bool Segment2d::intersectsLine(const Line2d &line, Vector2d *pos) {
|
|
Vector2d p;
|
|
if (getLine().intersectsLine(line, &p) && containsPoint(p)) {
|
|
if (pos)
|
|
*pos = p;
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
bool Segment2d::containsPoint(const Vector2d &point) const {
|
|
if (getLine().containsPoint(point)) {
|
|
return Rect2d(_begin, _end).containsPoint(point);
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
Segment2d &Segment2d::operator=(const Segment2d &other) {
|
|
_begin = other._begin;
|
|
_end = other._end;
|
|
|
|
return *this;
|
|
}
|
|
|
|
}
|